Lesson 1: Water Cycle

• Water vapor is water in its gas form, and is in the air that surrounds you. When water vapor cools, it changes into the liquid form of water.

• Water vapor and steam are not the same thing. Steam is above the air’s temperature. However, water vapor is the same temperature as the surrounding air. Steam is made when water boils.

• When steam meets cooler air, it turns into liquid water.

• The water cycle is the continuous movement of water on Earth.

• The sun provides the energy needed for the water cycle, and causes processes like ice melting, water evaporating, and winds blowing.

• The first stage of the water cycle is known as evaporation, which is the process of changing liquid water into water vapor.

• Heat causes the water to rise and evaporate, and as it reaches a higher altitude, it cools and changes back into a liquid. This is known as condensation, which is the second stage.

• The water and other particles in the atmosphere can then form clouds.

• The third stage is that water from the clouds can then fall as precipitation, which can be rain, snow, sleet, or hail.

• Some water can flow back into larger bodies of water as runoff, because of the force of gravity making it flow downwards.

• Other water can seep into the ground as groundwater, and can enter other bodies of water later, or they stay in the ground and end up creating an aquifer.

Lesson 2: Earth’s Freshwater